Currently, it is known to implement a predictive feedback compensation in an amplifier for suppressing distortion caused by supply voltage variations and output amplitude switching. A predictive step in the predictive feedback compensation can include measuring a varying or alternating current component of a supply voltage to predict an output pulse amplitude error for a pulse width modulator (PWM) input signal based on a prior PWM output signal, or the predictive step can also include measuring a varying or alternating current component of an output pulse amplitude for the PWM output signal to predict the output pulse amplitude error for the PWM input signal based on a prior PWM output signal.
It is further known to apply a predictive feedback system including a compensation circuitry for compensating for variations in a first and a second voltage in response to a measured average of a first and a second voltage and a measured difference between the first and second voltages. Measuring circuitry measures the average and the difference of the first and second voltages
U.S. Pat. No. 7,800,437 B2 discloses a method and system for closed loop feedback for pulse width modulated switching amplifiers using predictive feedback compensation for suppressing distortion caused by supply voltage variations.
WO 2004/062089 A2 discloses a delta-sigma modulator for driving an output stage is disclosed. The delta-sigma modulator operates M between first and second voltages and includes a loop filter, a quantizer, and a feedback loop coupling an output of the quantizer and an input of the loop filter. The feedback loop includes compensation circuitry for compensating for variations in the first and second voltages in response to a measured average of the first and second voltages and a measured difference between the first and second voltages. Measuring circuitry measures the average and the difference of the first and second voltages.